Electric connector



Feb. 28, 1939. A. F HOPKINS. JR

' ELECTRIC CONNECTOR Filed April 25, 1956 INVENTOR was vffkiw BY/Z ATTORNEY Patent ed Feb. 28,1939

"UNITED; STATES PATENT OFFICE;

mmst fimm Albert r. llonki'ns, In, Duluth, Minn. Application April 25, 1936, Serial lQ'o. #6393 4 Claims. larva-s s) (Granted under the act or March a,

- amended April so, 1928; :70 o. G. 75'!) The invention described herein may be manuiactured and used by or for the Government of the United States for governmental purposes without the thereon.

This invention relates to separable connectors for electrical conductors and more specifically to plug and socket connectors, such, for example, as attachment plugs as are used on lead wires from portable devices and sockets on feed conductors,

payment to me or any royalty as wall plugs, for supplying power to portable devices from a more or less permanent wiring system. v

In the use of attachment plugs of this char-- acter, the contact elements or projecting prongs thereof are frequently held so tightly by the, elements of the socket that the plug can only be withdrawn or'disconnected with diiilculty and force. In such instancesrthe user, when desiring D to disconnect or uncouple the attachment, usually pulls on the. feed conductors with-the result that binding screws and the wires are often broken or disconnected. In other cases the reverse is often the situation, namely, that the plug. and socket contact elements engage so loosely that theat- 'tachment plug is often accidentally pulled or jarred out of its operative position during the use of an electrical device connected thereto.

An object of my-invention is to provide an attachment plug and a cooperative socket embodying simple cooperative'latching means which operate efllciently to lock the plugin connected relation with a socket or wall plug. A further object is to provide an attachment plug of thetype that embodies a pair of prong-like terminals, projecting from-the plug and adapted to be inserted into a socket of a type that embodies contact elements that may be contacted by the plug prongs through slots.-

) A further object is the provision of connectin I elements which may be easily engaged and yet readily disconnected from each other without diillcultyl 'It is-an object of this invention to provide connectors of this type which when con-- n'ected will not be readily uncoupled without manual operation.

A further object-is to providean attachment plug in which the connections between the conductors and the terminals thereof are entirely r enclosed within the plug and to provide a plug" which is entirely devoid of screws, plates, pins,

rivetsand the like which are commonly used for the purpose of rigidly fixing the contact prongs to the body of the plug. By the elimination of the same, breakage and short-circuiting -is parallel relation and are oi. the usual rectangular 1883) as. j

avoided. the construction of the connector is greatly simplified.

Other objects, purposeaandiunctions of my, invention will be set forth in the following description, it being understood that the above gen- 5 eral statements of the obiects'of my invention are intended to generally explain the same without limiting itinanymanner.

In the accompanying drawing, illustrating/em 'bodiments of my invention,-'-

Figure 1 illustrates a base-end view of an at gtachnient plug, the projecting contact prongs being shown in cross-section, while-'- Figured illustrates the reverse end 01' a plug through which the conductors are intended to pass... g

. Figure 3 is a central horizontal section throughv one of the plugs.

Figure 4 is a view 'similarto Figure 3' but taken at right-angles thereto.

, Figureli is'a combined section and elevation.

of the cooperative socket for the D1118, and- Flgurefiisaviewsimilartothat oIFlgureB- except that it illustrates a screw-type of socket and a modified form of latching means.

Several embodiments and modifications within the scope oi! my invention are known to me, but according to that by which I have illustrated the invention and by which it may be practiced, I

provide (Figure 3) an attachment plug having a 30 body portion Ill composed oi distortable or resile ,ient insulating material and formed with an enlarged front-end or head portion II and a shank portion I 2 through which shank portion a conductor aperture Ibis provided, The aperture afi It extends into the head portion II where it is preferably enlarged, as at ll, so as to provide space for connecting conductors (not shown) cross-section in order to fit the more or less standard socket.

The cavity forming walls oithe plug are provided with an oblate shoulder, or an oblate groove or II at a point inward of the base end of the plug walls, the purpose of which is described hereinafter.

Rece's'ses 20 and 2| are provided within the.

walls of the plug into which the contact elements l5 and ii are inserted bycompressing or distorting the resilient plug. The contact elements may be, however, incorporated or molded directly within the insulating walls of the be replaced or repaired if necessary.

In either type the contact elements are firmly held in their normal position with respect to the plug by the action of the resilient material on the faces of the oiI-set portions.-

The recesses 2| and 2| enter the body portion of the plug from opposite sides of the cavity l4, preferably at right angles to the walls thereof, at a point inwardly adjacent the oblate annular shoulder, groove, or recess l9 and extend midway into the walls where they assume the angular shape or contour of the plug walls. The recesses 20 and 2! preferably terminate short of'the end of the shank l2 to prevent exposure of, or contact with, the contact element at the shank end of the plug.

Thus it will be seen that the shape of the recesses 20 and 21 and the conforming shapes of the contact elements I! and I6 serve as means for retaining the elements I! and I6 within the plug without rigid fixing means such as screws,

rivets and the like, which are-subject to breakage and short circuits.

I further provide an insulating plate or washer 22 having apertures 23 and 24 disposed substantially diametrically opposite each other (see Fig. 1). This plate is of'such size and shape as to be interlocked with the body portion of the plug when inserted within the oblate annular recess, groove, or shoulder ll.

As stated heretofore, the contact elements l5 and it are of such shape as to conform to the angles and curvatures of the recesses provided therefor within the walls of the plug. The contact elements I! and I6 are further provided with shoulders or offset jogs 25 and 28 where they converge into the projecting prongs l1 and I8 thereof. These shouldered or offset portions of the contact elements are adapted to abut the inner face of the plate 22 and thereby the plate serves as further means for locking and retaining the elements within the plug. The jogs in turn perniit the prongs to project through the plate apertures 22 and 24 and in a direction substantially parallel. The contact elements l5 and it are provided with means, such as illustrated at 25, Figure 4, preferably located on portions thereof within the housing or cavity it, to which conductors (not shown), lead into the plug through aperture l3, may be attached by means 26 such as a screw.

The prong portions I I and ll of the contact elements l5 and 16 are provided with means such as notches, catches or eyelets 21 and 28 for engaging cooperative means 29 and so such as lugs, notches or catches, provided on the contact elements II and 32, within the socket 33, to which the lead ,wires 34 are attached. In

addition to the cooperating engaging means of' the plug and socket, the socket may, if desired be provided with further means 35 and 36, such as an arcuate spring, for retaining the respective contact elements in a locked position. The engaging elements 29 and II are preferably formed with outwardly flared termini to provide for slipping engagement with the means 21 and 28. The notches while of sufiicient depth to insure against ordinary accidental separation of the plug and socket may, of course, be designed to permit forceful separation without injury to either plug or socket such as by a person tripping over the conductors.

Figure 5 illustrates a socket similar to that shown in Figure 6 except for the modified form of contact engaging. elements and except that Figure 6 illustrates the type of socket that may be screwed into another socket such as an ordinary light bulb socket. I a

The apertures 23 and 24 of disc 22 are guideways for the prongs H and I8 and serve to maintain the prongs in alignment. These apertures and 30 of the socket when manually operated.

'Another purpose of the disc 22 and the apertures 23 and 24 therein is to maintain proper and fixed distance between the prongs l1 and I8, that is, to prevent a spreading thereof beyond a predetermined maximum and to prevent a compression thereof beyond a predetermined amount. By the latter prevention the prongs cannot form a short circuit, that is, be compressed into contact with each other, but still are afforded sufllcient lateral movement, under compressions, to release the locking means.

The conductor passage [3, provided in the shank l2 ofthe plug is preferably of such-size and shape as to provide a relatively close fit with the conductor when installed.

In the operation of structures described it will be seen that the prongs irl and [8 are normally retained in a predetermined spaced relation but may be urged toward each other a predetermined distance by compressing the resilient body portion for releasing as described. By the relatively close fit of the shank l2 with the conductor it will be seen that the prongs i1 and I8, upon compression of the body of the plug at II, will move as though the contact elements were pivoted at the ends opposite the prongs, yet without the employment of a rigidly fixed pivot as heretofore employed.

The plug is provided, on the sides thereof in which the contact elements are incorporated,

-with substantially fiat faces 31 and 38 (Figures 1 and 2) to readily indicate the sides to be compressed in order to release the cooperative latching means. 7

By the foregoing description it will be seen that I provide a plug and socket having cooperative latching means to limit accidental disengagement; a plug which is devoid of metallic or other means for rigidly fixing or retaining the contact elements; a plug in which connections between conductorsand contact elements are shielded from exposure; a plug provided with means for preventing short circuiting between i Incombination an electrical plug having a relatively thin resilient oil-set wall with elongated oil-set recesses therein substantially parallel to the faces of said wall and electrical contact elei ments having ofl-set portions of substantially the same configuration as said wall and positioned within said recesses whereby said contact elements are retained in said plug by the action of the resilient material of said wall upon the D faces of said oil-set portions and in a predetermined spaced relation to each other, anda socket having orifices adapted to receive the contact elements of said plug, additional contact elements within said orifices, said contact ele- I ments being provided with cooperating interlocking means disengagement oi which is accomplished by compression of the wall of said plug whereby said contact elements are moved from the position determined by said plug.

o 2. An electrical plug comprising a hollow body portion having a conductor passage therein, contact elements having a portion retained within the walls of said body portion and having ends extending tree from the base of said body por- 5 tion in spaced relation, said free ends being providedwith means for assuring contact with a socket. a' disc, means within said hollow body portion whereby said disc is retained transversely.

relation but- 3. An electrical plug comprising an inherently resilient hollow body portion having a conductor e thereinto, a disc irictionally held in said hollow body portion, contact elements one end of each of which is of curvilinear configuration and retained thereby within said body substantially the full length thereof with their other ends extending from said body normally in spaced relation, said disc being formed with openings for guiding said extending ends toward each other upon compression, means between said disc openings to prevent a contact of said extending ends,

said contact elements also having jogged portions whereby said disc abuttingly assists in the retention oi the elements within the plug, and

means whereby when the embedded ends of the elements are pressed toward each other, their extending free ends will be correspondingly moved relative to each other.

4. An electrical connector including a manually compressible hollow body portion, consisting 01' a relatively thin resilient wall, contact elements having oil-set portions of curvilinear configuration interlocked within complementary -longitudinal recesses in said body portion. .an

oblate annular recess within said bodyportion,

and a disc within said oblate annular recess.

said disc having means for guiding said contact elements in alignment toward each other upon compression of said body portion, means for limiting the separation of said elements beyond a predetermined position, and means for preventing a contact between said contact elements upon the compression oi said body portion, in combinationwith a socket adapted to receive the ends of said contact elements and having meahs within said socket for locking and releasably retaining said contact element ends therein.

smear r. norms. Jr. 

